A supply chain is not a linear type of inter-firm structure but is often considered as a network. Business networks are underpinned by the firms' resources, social legitimacy and associated power, which are also seen in the adoption theories of business-to-business integration (B2Bi) in the supply chain. However, there appears to be scarcity of the discussion on the theoretical relationship between them. This paper aims to enrich the previous findings of technology adoption theories in a business-to-business context by proposing a structural model and using Structural Equation Modelling approach to test it. It focuses on the integrated supply chain to test, analyse and extend the adoption factors to the use of computer-based information systems (IS). The survey data were collected in the Taiwanese Information Technology Industry. The path analy- ses indicate the answers for three issues raised from the research framework and confirm the associations between a firm?s existing system support readiness and the network determinants outside organizational boundaries. Further, it identifies the interrelationships among these factors and indicates that some of them mediate the enterprises? behaviour on investments to increase current IS for B2Bi purposes.